Computer fails to post

[Fronzbot]

Hey all, I built this computer back in August for my girlfriend and it was working great up until recently when it won't post. Originally the CPU had a bent pin but I was able to get it back into the correct position and, as I said, it worked fine up until last week. The first thing I did was I reset CMOS by pulling the battery and placing the jumper across the "Clear Cmos" and held the power on for 1min (the power supply was NOT plugged into the wall). Still didn't post. Next I grabbed the video card and popped it into my system, it worked fine. Then I measured the voltages on the power supply connectors across a 10Ohm load and everything was fine there. I got my hands on another AM3 CPU and tested that in the system (thinking the original one with the bent pin had died) and the computer still didn't post.

Now here's the weird part. I decided to start testing the RAM, one stick at a time, one slot at a time. With the first stick I tried slots 1, 2, 3 and 4 and the computer didn't post. Just for the heck of it I popped that stick back in the first slot and voila! It booted up with no problem. I through the second stick in there and it didn't boot so naturally I'm thinking that second stick is the problem. I take it out, replicate the conditions of the successful test and... no post.

What the heck is going on here? I just pulled the CMOS battery and plan on keeping it out for the rest of the day just to see if that fixes anything (I've read on other threads on various forums that this has worked for some people exhibiting a similar problem). If there's anything anyone can do to help me, I'd be very grateful. I'm quite stumped!

As a note, I have either built or helped build about a dozen computers (which means I've done a lot of troubleshooting on them too ) so I'm not new to this, but I'm not totally experienced either. I also have a pretty good technical knowledge of computers as I'm an EE major and have access to some spiffy equipment so if there are any tests that go beyond typical troubleshooting problems that could be performed, please let me know as I can take the parts to one of my labs.

Thanks, again, for anybody who can try and help me out!

EDIT- WHoops! Forgot the computer specs!

CPU (now holds a Sempron 145) - Athlon II X245
RAM - 2x2GB OCZ DDR3 1600
Mobo - ASRock M3A770DE
PSU - Rosewill RV2-500 500W
VGA - Radeon HD4650

 

[Deleted member 67555]

You could try to..
Flash the bios from a USB or Flash card reader once you get it started....to the last needed bios

 

[Fronzbot]

I've only flashed a bios once, honestly, so would I still be able to do that if it doesn't even post (or, at the very least, i can't see the post)?

 

[Namslas90]

Reset CMOS again according to manual(page 22).
http://europe.asrock.com/manual/M3A770DE.pdf
You need to have the mobo battery installed and power supply off/unplugged to properly reset cmos.

 

[Techtu]

sounds like everything has been reset just fine to me... I'm going to go with my theory - OCZ RAM does not boot in all boards from the moment they are fitted, you may find that your motherboard can cope with that RAM just fine however the problem is some boards don't like booting OCZ RAM due to something to do with the voltages as far as I am aware. So now here comes the solution (lucky you )

You will need another stick of RAM, possibly try use one a little slower than your OCZ stick's, pop it in the rig and boot the thing up, immediately enter BIOS and change the RAM settings to match those listed on the OCZ modules - if you need any further help with the settings just let us know

P.S I may not be very accurate with my theory of why it doesn't boot at the moment but I know I am on the right tracks here and am pretty sure you'll have the rig up and running again if you follow what I said.

 

[Fronzbot]

sounds like everything has been reset just fine to me... I'm going to go with my theory - OCZ RAM does not boot in all boards from the moment they are fitted, you may find that your motherboard can cope with that RAM just fine however the problem is some boards don't like booting OCZ RAM due to something to do with the voltages as far as I am aware. So now here comes the solution (lucky you )

You will need another stick of RAM, possibly try use one a little slower than your OCZ stick's, pop it in the rig and boot the thing up, immediately enter BIOS and change the RAM settings to match those listed on the OCZ modules - if you need any further help with the settings just let us know

P.S I may not be very accurate with my theory of why it doesn't boot at the moment but I know I am on the right tracks here and am pretty sure you'll have the rig up and running again if you follow what I said.

Ah, right. I have OCZ in my personal rig and was having a ton of headaches preventing blue screens and all that jazz until I realized they needed 2.1V rather than the default 1.8 (on my mobo). That was certainly a problem. Now I just took a look at the RAM in the computer already and it requires 1.65V which could be a problem if the mobo is defaulting to 1.8. I'll try booting with another DDR3 stick from my roommate when he gets back in a few hours- hopefully that's the problem.

 

[Techtu]

Ah, usually it's the other way around the motherboard isn't supplying enough power to the RAM to boot - not it's powering too much, but I'm still going to stand in my corner

Reason being that the voltage is just simply set too high for the likings of the RAM module/s.

So again, post back in a few hours or whenever your room mate comes back and let us know the results.

 

[panchoman]

Reset CMOS again according to manual(page 22).
http://europe.asrock.com/manual/M3A770DE.pdf
You need to have the mobo battery installed and power supply off/unplugged to properly reset cmos.

what he said..

removing the cmos battery & using the jumper is just doing 2 things, one which is improper & countering the efforts of the 2nd..

consider it like this - you've got your computer on and you pull the plug without shutting down.. crap got stuck on the ram and hdd and isn't as clean when you restart then if you had just used a proper restart..

similairly, the cmos method is more of like trying to make the mobo forget the settings and then having to default.. it's not that great, and is usually a last resort..

on the other hand, the jumpers are there so that you can specifically tell the motherboard to reset itself, meaning it will cleanly restore the bios settings.

sorry for that huge lecture lol,

anyhow,

did you test the motherboard and what's called the "open-system" style? check for screws or any standoffs,etc. etc. which may be causing motherboard grounds. try taking the motherboard out and inspecting it for any damage, etc. etc., and do your testing out of the case...

 

[nailzer]

Any beeps from the computer? Long beeps, short beeps?

 

[Fronzbot]

Sorry for the delayed reply, I've been very busy and haven't gotten around to testing until tonight.

@techtu- I took the sticks in the "broken" computer and placed them in my roommate's computer (the mobo has DDR3 1600 support) and it booted up fine. I then tried his slower sticks (DDR3 1333) in the "broken" computer and nothing happened. Bad RAM this problem is not (kinda wish it was, though)

@panchoman- Tried it, still didn't work (unsurprisingly). As for the open-case method, I haven't yet, it is my next step when I have some more time (probably the weekend).

@nailzer- no beeps. Only time it did was when the computer successfully booted that one time and I was so excited I don't remember what the pattern was

Anyone have any other ideas? As I said, I'll be doing the open-case method this weekend. I'm just really stumped right now, to be honest.

 

[Fronzbot]

Open case method produced the same results as before. What else can I do short of replacing the motherboard? That's the only thing I am unsure of as to whether or not it works. The only other thing is maybe the bios chip needs a flash to the most recent version, but I can't do that if I can't even get to post! Very frustrating! I'm tempted to take the thing to Best Buy in the hopes that they have a mobo that can be tested with it. If I know the problem I can fix it, but I just can't get to that point.

 

[Techtu]

If you think it's the BIOS why not slap another (slower) compatible processor in the board, boot it - flash it - job done it (that's if you are correct on suspecting the BIOS is old.

If your room mate has the same socket CPU/motherboard as you then you could try your CPU in his board, that then would see if it was your motherboard for sure - without the need to go to best buy...

 

[Fronzbot]

If you think it's the BIOS why not slap another (slower) compatible processor in the board, boot it - flash it - job done it (that's if you are correct on suspecting the BIOS is old.

If your room mate has the same socket CPU/motherboard as you then you could try your CPU in his board, that then would see if it was your motherboard for sure - without the need to go to best buy...

I have not been able to find anyone with an AM3 motherboard (intel fanboys around campus it seems ). Now, I did put the slower Sempron in the computer and it's still there, but how can I flash the bios without getting to post? I've only ever flashed once so it is pretty foreign to me, are there any really good links you could point me to to help? I checked the manufacturer's website but the directions were crap and involved at least getting to the post screen (which is not happening here) so that was useless. I was under the impression that you needed to at least see the post screen in order to flash, am I wrong (I hope I am!)?